1. Field of the Invention
The present invention relates to a rapid onset formulation, preferably in form of an enterically coated tablet, for a medicament comprising a synergistic duo of active ingredients namely, doxylamine succinate and pyridoxine HCl, hereinafter referred to as xe2x80x9cDS-Pxe2x80x9d. DS-P is useful in the treatment of nausea and vomiting, especially, but not limited to, during pregnancy, hereinafter referred to as xe2x80x9cNVPxe2x80x9d. Thus the present invention is concerned with all known and future therapeutic indications of DS-P.
2. The Prior Art
Pharmaceutical formulations of DS-P are known. The current formulation, commercially available in Canada under the name Diclectin (Duchesnay Inc.) comprises the following active ingredients: pyridoxine HCl and Doxylamine succinate. It additionally comprises the following excipients: lactose, microcrystalline cellulose, magnesium trisilicate, silicon dioxide and magnesium stearate.
Diclectin is the world""s most studied drug in regard to its safety during pregnancy. Because of its excellent safety profile, Diclectin is the drug of choice for the treatment of NVP. The current formulation is sugar coated and suffers from drawbacks, one of which being its delayed onset of action. However, the current formulation once ingested, can take more than 4 hours before the two active ingredients (pyridoxine HCl and doxylamine succinate) reach nearly full dissolution in the small intestines, where it is absorbed. This delay is often considered too long for patients, such as women suffering from NVP, who require urgent relief of symptoms.
Another drawback of the current formulation is related to patient compliance. Women suffering from NVP often complain of hyper olfaction, which means that various odors and tastes can trigger nausea or vomiting problems. The smell and taste of sugar on the current sugar coated formulation as well as the use of organic solvents and phthalates in the preparation of the currently used enteric coating, bothers many pregnant women to the point where the intake of the drug is essentially inhibited.
The size of the currently available tablet is also problematic. A smaller size tablet would improve patient compliance since women suffering from NVP often have problems swallowing. Furthermore, a smaller tablet looks less harmful than a bigger one and patients will have the impression that they are taking a lesser amount of drug. This will in turn significantly increase patient compliance.
Finally, the current formulation contains lactose. This is objectionable for those patients suffering from lactose intolerance.
Thus, it is desirable to provide patients suffering from nausea and vomiting an improved rapid onset formulation overcoming the drawbacks of the prior art.
However, since DS-P is orally delivered as an enteric coated tablet, the novel oral formulation must transit through the stomach unscathed and rapidly release both active ingredients once the dosage form reaches its intended destination, namely the intestines.
The main challenge surmounted by the present invention was to arrive at a dosage form capable of overcoming the drawbacks of the prior art while simultaneously delivering the synergistic duo of active ingredients for rapid onset. It was also important to provide a formulation exhibiting similar dissolution curves for both active ingredients so as to avoid the dissolution of one active ingredient to the detriment of the other. This was important in view of the synergistic therapeutic effect of the duo of active ingredients.
In general terms, the invention provides a new aqueous enteric-coated formulation comprising DS-P, the formulation exhibiting a dissolution profile indicative of a rapid onset.
The invention also seeks to provide a pharmaceutical composition having specific in-vitro dissolution profiles indicative of rapid onset of the active ingredients. The pharmaceutical composition being suitable for simple and reproducible manufacture.
Further scope of applicability will become apparent from the detailed description given hereinafter. It should be understood however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.